Introduction. After studying the magnetic properties of [Dy(L)(OAc)₂]NO₃·2H₂O (L = 2E,6E,9E,13E-3,6,10,13-tetraaza-1,8(2,6)-dipyridinacyclotetradecaphane-2,6,9,13-tetraene), its single-molecule magnet behavior under an optimal field of 2000 Oe was revealed. Furthermore, luminescence measurements indicated that the ratio between the integrated intensity of the macrocyclic Schiff base and that of the Dy^{3+ 4}F_9/2 → ⁶H_13/2 transition can define a secondary luminescent thermometer, with a maximum relative thermal sensitivity value of 2.3% K⁻¹. In view of these interesting properties, we changed the counterion from nitrate to tetraphenylborate to see its influence.

Synthesis and methods. Here, we present the result of the synthesis and characterization of the dysprosium complex [DyL(OAc)₂]BPh₄. It was obtained by a template synthesis of 2,6-pyridinedicarboxaldehyde, dysprosium acetate tetrahydrate and ethylenediamine, and a subsequent reaction with sodium tetraphenylborate. Single crystals of the compound were obtained via the recrystallization of the solid in dichloromethane with an Et₂O layer in the fridge. Then, it was characterized by elemental analysis, IR spectroscopy and single X-ray diffraction techniques.

Results. Two slightly different moieties of [DyL(OAc)₂]⁺ are present in the unit cell, alongside tetraphenylborate anions, but no other species are present. Thus, the crystal packing lacks classic H bonds, whereas many C-H···O and C-H···π interactions are present in the crystal packing scheme. This cationic complex shows a decacoordinate metal center, almost forming a distorted tetradecahedron. The characterization of this Dy^III complex allows us to compare its properties with those of other closely related species.

Conclusion. The presence of such a hydrophobic counterion strongly influences the crystal packing of this species, but is does not have such an intense impact on other features, mostly related to the [DyL(OAc)₂]⁺ cation.

Arguably the most famous type of noncovalent interactions, hydrogen bonds are very important in numerous chemical and biological systems, including the ones with aqua complexes. Metal coordination enhances the strength of hydrogen bonds of water by amplifying the positive charge on interacting hydrogen atoms. In this work, the hydrogen bonding ability of water molecules acting as bridging ligand in metal complexes was studied by the means of crystallographic analysis, as well as density functional calculations.

A survey of crystal structures of high quality from the Cambridge Structural Database (CSD) was performed using the ConQuest program to find hydrogen bonds between bridging water in metal complexes as a hydrogen bond donor and the water molecule as a hydrogen bond acceptor. The energies of hydrogen bonds found in the CSD were calculated in the Gaussian 09 suite of programs using the dispersion-corrected B97D density functional and the def2-TZVP basis set.

A total of 88 hydrogen bonds of bridging water in metal complexes was found. The majority of these hydrogen bonds have short H∙∙∙O distances, mostly between 1.7 Å and 1.9 Å, with several examples even below 1.6 Å. Additionally, these hydrogen bonds possess a high degree of linearity, with the majority of O-H∙∙∙O angles between 165° and 175°. These geometrical parameters indicate short and linear, and therefore strong, hydrogen bonds. DFT calculations show that these interactions are indeed very strong. Specifically, neutral complexes containing bridging water form hydrogen bonds with free water that can reach an energy of -15.4 kcal/mol. This is significantly stronger than hydrogen bonds of neutral metal complexes of non-bridging water, which do not surpass -10.0 kcal/mol.

The joined crystallographic and computational study demonstrates the enhanced ability of bridging water in metal complexes to act as hydrogen bond donor.

Abstract: The HT- Pb₂GeS₄ (SG I-43d) is a prospective material for investigation. The structure of HT- Pb₂GeS₄ crystallizes in cubic symmetry. The positions 24d, 16c, and 48e can be modified through the substitution of atoms Pb and S. We investigated the crystalline structure of four compositions, Pb_1.9Sn_0.1GeS_3.52Se_0.48, Pb_1.86Sn_0.14GeS_3.32Se_0.68, Pb_1.82Sn_0.18GeS_3.16Se_0.84, and Pb_1.58Sn_0.42GeS_3.64Se_0.36, changing the cation and anion sublattice simultaneously.

Samples with the nominal compositions of Pb_2-xSn_xGeS_4-ySe_y (x = 0.1, 0.14, 0.18, and 0.42; y = 0.36, 0.48, 0.68, and 0.84) were prepared by melting high-purity Pb (shot, 99.99 %), Sn (shot, 99.99 %), Ge (shot, 99.999 %), S (shot, 99.99 %), and Se (shot, 99.99 %) in quartz containers evacuated to a residual pressure of 10^–2 Pa. The total mass of every sample was 1 g. The ampules with the stoichiometric mixtures of elements were heated up to 1423 K at a rate of 12 K/h; kept at this temperature for 4 h; cooled down to 773 K at a rate of 12 K/h; annealed at this temperature for 500 h; and quenched in cold water without breaking the containers.

The substitution in cation and anion sublattice on the Pb₂GeS₄ crystal structure leads to the increase in the volume of the lattice from 2794.9 Å to 2852.2 Å due to the change of y. The lattice parameter a changes from 14.086 Å to 14.1816 Å. A distortion of the cation sublattice is also observed.

Hence, such peculiarities of the crystal structure may improve some thermoelectric and optical properties.

Glass ceramics, formed through the meticulous control of glass crystallization, have become indispensable in modern life owing to their multifaceted utility. Their shape and size adaptability, exceptional stability across various conditions, ease of fabrication, and consistent performance render them pivotal in addressing pressing environmental concerns. These qualities position them as potential solutions to urgent challenges.

Phosphate glasses, widely utilized, offer fertile ground for exploration in photocatalysis with the integration of TiO2. In our study, glasses with varying TiO2 concentrations (0%, 2.5%, 5%, 7.5%, and 10%) were melted at 1200°C. This process induces the transition from an amorphous state into a glass ceramic state within a temperature span encompassing both melting and crystallization. Analysis of thermal, structural, and morphological attributes reveals that augmenting TiO2 content in phosphate glass amplifies its photocatalytic efficacy, resulting in the accelerated degradation of organic pollutants under light exposure. These findings underscore the pivotal role of TiO2 in enhancing the environmental performance of glass, thus paving the way for sustainable and innovative advancements.

In summary, the evolution of glass ceramics from controlled crystallization techniques heralds a new era in addressing environmental challenges. Incorporating TiO2 into phosphate glasses is promising for advancing photocatalytic applications, offering a pathway to mitigate environmental degradation. As research progresses, these materials are poised to play a pivotal role in fostering sustainability and innovation.

Biotite mica mineral is a common rock-forming mineral that is generally found in metamorphic rocks, but also in igneous rocks. In addition to their high tensile strength, high thermal stability, layered form, and high resistance to chemical and environmental degradation, mica materials also have high electrical resistance. They possess interesting dielectric properties that make them ideal for a number of applications, particularly as a low-cost substitute material for energy storage systems, due to their exceptional insulating characteristics that allow for the transmission of electrical force without conduction. The aim of this article is to investigate the possibility of recovering biotite from granite waste, as part of a circular economy approach, by using a less polluting technique—that of high-intensity dry magnetic separation. Particle size analysis, inductively coupled plasma spectrometry, and X-ray diffraction were used for physicochemical and structural characterization. The findings of this study reveal promising results in terms of content and yield, underlining the effectiveness of this method for biotite recovery compared with other conventional techniques that are used to obtain a high degree of mica biotite purity, as is required in the field of energy storage. This technique is also useful in terms ofgetting rid of waste that represents a heavy environmental burden and has no economic value.

Metal–organic frameworks are a class of porous materials that are widely used in various fields of science, such as gas sorption and separation, sensing, catalysis, and others.

Currently, most MOFs are created on the basis of hard aromatic carboxylic acids or N-donor ligands. However, ligands with flexible aliphatic bridges that provide conformational mobility to the ligand are promising. This mobility can be transferred to the MOF, or at least the flexibility of such a ligand can lead to its variability and atypical structure. Such structures may exhibit unusual gas adsorption properties.

Layered MOFs have a special feature—their layers are not bound by rigid ligands, so they can "breathe", that is, they can move relative to each other. In the initial state, a MOF may be a low-porosity or non-porous compound, but at gas pressure, it begins to show a "gate-opening" effect, which can lead to the selective adsorption of gases.

Our work is devoted to the study of layered MOFs based on 1,3-bis(imidazolyl)propane (bip) containing a -C3H6-alkyl group. Due to its conformational mobility, bip acts as a bridging ligand that connects two metal atoms into one secondary building block (SBU). Secondary building blocks M (bip)₂²⁺ (M = Cd, Cu) form a layered mobile structure with the help of functionalized terephthalic acids (bdc-NO₂).

The sorption characteristics of these compounds are of great interest to the research community. As part of our work, we investigated the adsorption of industrially important hydrocarbons such as methane, ethane, ethylene, acetylene, propane, and propylene at different temperatures. Using the example of C₃-hydrocarbons, we show an anomalous dependence of the amount of adsorbed gas on temperature. Usually, as the temperature increases, the volume of sorbed gas decreases. In the case of the studied compounds, an inverse, more complex dependence is observed.

The features of the semiconducting state formation in oxysulfostibnites of the rare earth metals GdSbS₂O, DySbS₂O, HoSbS₂O, and ErSbS₂O have been investigated. Our theoretical calculations were performed in the framework of the GGA+U method accounting for strong electron correlations in the 4f shell of rare earth metals and they showed that these compounds, GdSbS₂O [1], DySbS₂O, HoSbS₂O, and ErSbS₂O [2], are semiconductors with a small direct gap at high-symmetry point X. For the first time, it was found that for the band gap formation in the rare-earth-metal oxysulfostibnites, it is important both to optimize the crystal structure and to take into account the spin--orbit coupling. The rare-earth-metal oxysulfostibnites, along with their layered structural analogues oxysulfides, due to their distinctive properties, can be widely used in biomedicine, photoluminescence, and other fields. Our calculations were performed on the Uran supercomputer at the Institute of Mathematics and Mechanics of the Ural Branch of the Russian Academy of Sciences. This research was carried out within the framework of the state assignment of the Ministry of Education and Science of Russia, theme “Electron”, No. 122021000039-4.

1. S.T. Baidak, A.V. Lukoyanov, “Semimetallic, half-metallic, semiconducting, and metallic states in Gd-Sb compounds”, International Journal of Molecular Sciences 24, 8778 (2023), https://doi.org/10.3390/ijms24108778
2. S.T. Baidak, A.V. Lukoyanov, “Formation of a semiconductor state in oxysulfostibnites RSbS₂O at R = Dy, Ho, Er”, Journal of Experimental and Theoretical Physics (accepted, 2024).

1. Introduction–Sulfanilamide’s were the first chemical drugs used as preventive and therapeutic agents against various infection diseases [1]. They generally act as structural analogues of para-aminobenzoic acid and therefore inhibit dihydropteroate synthase [2]. After the discovery of Penicillin [3], their use decreased significantly. Nevertheless, in recent years, their synergistic activity has gradually attracted the attention of researchers [4-5]. In this work, we report synthesis, crystal structure, ADME prediction, molecular docking, antibacterial and toxic activities of new sulfanilamide derived Schiff base (SB), i.e. 2-(2-hydroxyphenyl)quinoline-6-sulfonamide (HPQS).

2. Experimental - HPQS is synthesized through a two-step process, viz, reflux and solvothermal methods. In the first step, condensation reactions similar to those reported for similar SB were carried out [6]. The second step involved using a Teflon-lined autoclave [7]. GOLD software [8] was used to conduct docking investigations. ADME parameters and drug-likeness were estimated using SwissADME [9].

3. Results and Discussion - Single crystal X-ray diffraction indicates that the HPQS crystallize in P2₁/c space group, with two molecules in the asymmetric unit (A and B). The crystal structure features N—H⋯O, C—H⋯O and C—H⋯? hydrogen bonds and ?–? stacking interactions. Additionally, Drug-likeness and pharmacokinetics parameters revealed that the compound exhibited favorable ADME properties. Finally, molecular docking study was carried out to investigate the possible binding mode of the sulfanilamide derivative. Molecular docking studies and biological screening of HPQS explored its diverse potential application as antibiotic agent. It showed high negative binding scores due to the presence of different hydrogen bonding types. Therefore, docking studies revealed strong interactions and high binding potencies and affinities against the tested macromolecular receptors.

4. . Conclusions - In this study, we have reported the synthesis and caracterisation of new SB derived from sulfanilamide (HPQS). Considering the findings of the study, it has been proven that this new compound constitutes a promising therapeutic agent capable of managing bacterial infections.

Through a hierarchical modelling scheme, we determine a phase diagram of attractive rod-like polymers in three dimensions, comparing them with their freely jointed polymer counterparts [1,2]. Rod-like polymers are modelled as linear chains of tangent hard spheres whose chain stiffness is governed by a tuneable harmonic potential for the bending angle [3]. Employing the Simu-D suite [4], extensive Monte Carlo simulations provide a surprisingly rich collection of distinct crystal polymorphs, which can be finely tuned according to the range of attraction. These crystal polymorphs, identified by the Characteristic Crystallographic Element (CCE) norm [5], include face-centred cubic, hexagonal close-packed, simple hexagonal, and body-centred cubic structures and their combinations, as well as the establishment of the Frank–Kasper phase for freely jointed chains. Furthermore, employing the concept of cumulative neighbours of ideal crystals, a simple geometric model is proposed as a function of the range of attraction to accurately predict most of the observed structures and the corresponding transitions [2]. A geometrical analysis is provided of the characteristics of the self-assembled polymer clusters and crystals under conditions corresponding to a vacuum. Therefore, the present study demonstrates, at a fundamental level and in a highly idealised model, the capacity to fine-tune a single interaction parameter to employ for the design of polymer crystals with tailored morphologies.

[1] M. Herranz, M. Santiago, K. Foteinopoulou, N.C. Karayiannis and M. Laso, Polymers 12, 1111 (2020).

[2] M. Herranz, C. Pedrosa, D. Martínez-Fernández, K. Foteinopoulou, N.C. Karayiannis and M. Laso, Phys. Rev. E 107, 064605 (2023).

[3] D. Martínez-Fernández, M. Herranz, K. Foteinopoulou, N.C. Karayiannis and M. Laso, Polymers 15, 551 (2023).

[4] M. Herranz, D. Martínez-Fernández, P. Ramos, K. Foteinopoulou, N.C. Karayiannis and M. Laso, Int. J. Mol. Sci. 22, 12464 (2021).

[5] P. Ramos, M. Herranz, K. Foteinopoulou, N.C. Karayiannis and M. Laso, Crystals 10, 1008 (2020).

Dense packings of semi-flexible polymer chains are researched through the Monte Carlo suite Simu-D [1] in extremely confined monolayers, effectively corresponding to two-dimensional films [2]. We systematically study the effect of chain stiffness on the packing ability and the emergence of local and global orders of semi-flexible polymers, modelled as linear chains of tangent hard spheres, the chain stiffness of which is tuned by a harmonic bending potential [3]. Thus, the limit of random close packing (RCP) is explored as a function of the equilibrium bending angle, while the local and global order of the emergent structures is quantified by the degree of crystallinity [4] and the nematic and tetratic orientational order parameters [5], respectively. A multi-scale wealth of structural behaviour is observed for the different semi-flexible systems studied, which is inherently absent in packings of athermal individual monomers, and which is surprisingly richer than that in three dimensions under bulk conditions. As a general trend, an isotropic to nematic transition is observed at sufficiently high surface coverages. As surface coverage further increases, the nematic phase is followed by the establishment of a tetratic state, which in turn marks the onset of RCP. For chains with right-angle bonds, the incompatibility of the imposed bending angle with the neighbour geometry of the triangular crystal (the densest structure in two dimensions) leads to a singular intra- and inter-polymer tiling pattern made of squares and triangles. The present study could serve as a step towards the design of hard colloidal polymers with tuneable behaviour for 2D applications. [1] M. Herranz et al., Int. J. Mol. Sci. 22, 12464 (2021). [2] C. Pedrosa et al., J. Chem.Phys. 158, 164502 (2023). [3] D. Martínez-Fernández et al., Polymers 15, 551 (2023). [4] P. Ramos et al., Crystals 10, 1008 (2020). [5] D. Andrienko, J. Mol. Liq. 267, 520-541 (2018).